It would not be good, but it wouldn't be Bhopal. And there are still plenty of factories making pesticides.
Also that statement of 70 meters seem very off, looking at the size of the building. What leads to suffocation is the inability to remove co2 from your body rather than lack of oxygen, and thus can be life threatening even at 4% concentration. It should impact a much much larger area.
Also a 'puncture' is very different from the gasbag mysteriously vanishing from existence; My only other thought is that in cold regions (I saw wisconsin mentioned in the article) CO2 does not diffuse quite as fast and sometimes visibly so...
I don't know the safety limits for this quantity, I hope the "70 meters" claim was by someone who modelled it carefully rather than a gut check.
How did they calculate that evacuation distance? CO2 is heavy. That little house about 15m from the bubble needs to be acquired.
The topography matters. If the installation is in a valley, a dome rip could make air unbreathable, because the CO2 will settle at the bottom. People have been killed by CO2 fire extinguishing systems. It takes a reasonably high concentration, a few percent, but that can happen. They need alarms and handy oxygen masks.
Installations like this probably will be in valleys, because they will be attached to wind farms. The wind turbines go in the high spots and the energy storage goes in the low spots.